[libpng16] Added symbol prefixing that allows all the libpng external symbols

to be prefixed (suggested by Reuben Hawkins).  This is work in progress that
breaks some non-configure builds.

scripts/intprefix.dfn

@@ -0,0 +1,18 @@
+
+/* intprefix.dfn - generate an unprefixed internal symbol list
+ *
+ * Last changed in libpng version 1.6.0 [January 30, 2012]
+ * Copyright (c) 2012 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_INTERNAL_DATA(type, name, array)\
+	PNG_DEFN_MAGIC-name-PNG_DEFN_END
+
+#define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+	PNG_DEFN_MAGIC-name-PNG_DEFN_END
+
+#include "../pngpriv.h"

scripts/macro.lst

@@ -0,0 +1,3 @@
+get_uint_32(buf)
+get_uint_16(buf)
+get_int_32(buf)

scripts/pnglibconf.dfa

@@ -161,6 +161,12 @@ setting USER_VERSIONINFO_LEGALTRADEMARKS
 
 setting API_RULE default 0
 
+# This allows a prefix to be added to the front of every API functon name (and
+# therefore every symbol) by redefining all the function names with the prefix
+# in a new file "pngprefix.h"; this file must be installed in png.h if this
+# facility is used.
+setting PREFIX
+
 # Default to using the read macros
 
 setting DEFAULT_READ_MACROS default 1

scripts/prefix.dfn

@@ -0,0 +1,20 @@
+
+/* prefix.dfn - generate an unprefixed symbol list
+ *
+ * Last changed in libpng version 1.6.0 [January 30, 2012]
+ * Copyright (c) 2012 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+	PNG_DEFN_MAGIC-name-PNG_DEFN_END
+
+/* The configuration information *before* the additional of symbol renames,
+ * the list is the C name list; no symbol prefix.
+ */
+#include "pnglibconf.out"
+
+#include "../png.h"